OFFSET
2,1
COMMENTS
Twin hearts (6c4a type) is one of total 17 distinct patterns appearing in 3X2 coins where each pattern consists of 6 perimeter parts from each coin and forms a continuous area.
LINKS
Kival Ngaokrajang, Illustration of initial terms (U)
FORMULA
a(n) = n^2 - 4*A230548(n).
G.f.: x^2 * (-3*x^10 - 4*x^8 + 3*x^7 + 8*x^6 + 4*x^5 - x^4 + 4*x^3 + 4*x^2 + 5*x + 4)/(1+x^3)*(1-x^3)^2*(1-x^2). (conjectured). - Ralf Stephan, Oct 30 2013
PROG
(Small Basic)
col = 1
row = 0
For n = 2 To 100
add = 0
If Math.Remainder(n, 2) * Math.Remainder(n, 3) <> 0 Then
add = 1
EndIf
If n >= 4 And Math.Remainder(n, 2) = 0 Then
col = col + 1
EndIf
If n >= 3 And Math.Remainder(n, 3) = 0 Then
row = row + 1
EndIf
U = n * n - (col * row + add)*4
TextWindow.Write(U+", ")
EndFor
CROSSREFS
KEYWORD
nonn
AUTHOR
Kival Ngaokrajang, Oct 23 2013
STATUS
approved